Cooker



FIG.4

FIGQ 2 May 21, 1946.

R. HERMANN COOKER Filed Feb. 10, 1943 Y 3 Sheets-Sheet 1 RICHARD HERMANN INVENTOR ATTORNEY q I r o u ll- I n V Q May 21, 1946. R. HERMANN 2,400,643

I COOKER 7 Filed Feb. 10, 1943 s Sheets-Sheet 2 Rucumm HERMANN |NVENTOR ATTORNEY May 21, 1946. I HERMANN 7 2,400,643

COOKER Fi ed Feb. 10, 1945 a Sheets-Shet s Rvcumw HERMANN INVENTOK ATTORNEY Patented May 21, 1946 UNITED STATES PATENT omen Richard Hermann,

Application February 10,

6 Claims.

This invention relates to improvements in cookers.

In the ordinary gas cooker which is in general use the top or hot-plate comprises a number of gas rings or burners arranged below skeleton supports for sauce pans or other cooking utensils. The utensils are heated directly by the flames and hot products of combustion from the burners and tests show that the efficiency of this method of'heating is betweeneo and 50' per cent. Part of the loss is due to the fact that the rate of heat transference from a gaseous medium to a solid medium is comparatively low and the products of combustion are only in contact with the surface of the utensil for a relatively short period of time as they flow over it,

Cookers are also known in which the burners are arranged below imperforate plates or rings on which the utensils are placed but-the plates or rin s are made of cast iron to resist corrosion by the products of combustion and cast-iron is a comparatively poor conductor of heat and there is a considerable heat loss between the burner and the utensil.

Similar imperforate plates or rings of cast-iron are used in solid fuel cookers, the plates or rings in some cases having depending ribs or fins over which the hot products of combustion from the fire flow but as the plates or rings are made of cast iron there is the same heat loss.

One object of my invention is to provide a hot plate in which the overall efficiency is substantially increased, and another object is to provide an efiicient hot plate having a solid top similar to that of a cooking range for supporting the cooking utensils.

According to my invention a heated ring or plate to receive a cooking utensil comprises an imperforate or substantially imperforate plate or also having depending fins, ribs or studs and. having incorporated in it material of a higher heat conductivity than the material of which the plate is made.

The fins or ribs and the lower surface of the plate provide a very large surface for the reception of heat from a burner or burners below the plate and the heat is transferred by the material of high heat conductivity to the upper surface of the plate from which it is transferred by direct conduction and radiation to a utensil placed on the plate.

The plate will usually be made of cast-iron which is highly resistant to corrosion by the products of combustion but has a relatively low heat conductivity whle the material of higher heat Sutton GoldfieldyEngland 1943, Serial No. 475,429 Great Britain February 12, 1942 conductivity may be copper or aluminium, or it may be a metal, metal alloy or salt having a melting point lower than the normal working temperature of the plate and enclosed within a space or spaces in the plate.

These and other features of my invention are described below in more detail with reference to the accompanying drawings in which a number of practical forms of my invention are illustrated by way of example.

In these drawings:

Figure 1 is a plan in half section of a gasheated hot-plate in accordance with my inven tion.

Figure 2 is a vertical of Figure 1, u

Figure 3 is a plan of an alternative arrangement.

Figure 4 is a vertical section on the line 5-4 of Figure 3.

Figures 5 to 12 are fragmentary sections showing various ways of providing inserts of high heat conductivity in a cast-iron plate.

Figure 13 is a plan inhalf section of another form of hot-plate.

Figure 14 is a vertical section of the plate shown in Figure 13.

In the arrangement shown in Figures 1 and 2, I0 is a cast-iron hot plate having a flat top to receive a cooking utensil and having on its under surface integral depending radial ribs or fins. To avoid having a large mass of metal at the centre alternate ribs ll extend to the centre of the plate while the intermediate ribs l2 terminate short of the centre. The ribs are thickened at certain points to form substantially cylindrical studs l3 each of which encloses an insert M of section on the line 2---2 a metal of high heat conductivity such as copper or aluminium. These inserts are cast into the plate b placing them in the mould and casting the iron around them so that they become integral parts of the plate. The length of the inserts is such that they extend from adjacent the studs to or adjacent to the upper surface of the plates. The spacing and dimensions of the ribs and of the studs and inserts are preferably so selected that there is a substantially uniform distribution of heat over the surface of the plate.

The plate is supported by portions of the outer ends of certain of the ribs l l and I2 resting on a ring l5 surrounding the gas burner It by which theplate is heated. There is preferably a gap 11 between the peripheral edge of the plate and the'cooker-top l8 to avoid direct conduction of drilled in the studs the'upper end of ameter to give uniform heatwdistribution on the position shown'in dotted-lines at-.l;9. J g In the arrangementshown in 'FiguresB ,and'4 a cast-iron plate 20 is formed with a series of integral spaced depending studs 2| in each off j which is fitted an insert of high heat conductivity." As shown on the left of Figure 4 the studs" are drilled vertically from the up aer-surface-i f the copper or aluminium may be inserted in" the form of powder which is subsequently sintered to Instead of the bores being they may be formed in the gether" under heat.

castingoperation; v t

As shown on the right of Figure 4 the studs ,2l from the bottom and after the inserts 23 are fitted the openings are closed by steel or iron plugs'24'welded in place to protect the lower ends of theinserts.

A substantial t which may serve to support Figure 5 shows on avlargeriscale a stud BihaV-f ing a bore into which an insert 29 of copper or aluminium is pressed or driven, the bore being closed by a ferrous plug, 30 welded in place. V 1 g In Figure 6 the bore in the stud ameter than the is of larger di modification inwhich the per end of the insert 34 is threaded at 35 into the conduction of heat Figure 8 shows an arrangement in which the through to the upper of the bore may be countersunk and the upper end of the insert rivetted over into it. I

Figure 9vshows a very similar arrangement but the insert 4! ing screwed'with a thread of the same pitch. -F'igurei10 shows an arrangement in which a the lower end of 5 the same time ensure vrapid is reduced in di- L In all forms of the bore and insert extend right through the plate "andthe stud. The top and bottom ends of the L bore are countersunk and the ends, of the insert plate that surface is preferably ground flat after the inserts have been fitted. 1

. The hot plate, shown in Figures 13 and. 14s is a hollow member made in two parts. The upper part is a flat cast-iron plate 5| having a peripheral depending flange 52 and a seriesof shallow liquid at the normal working temperature of the r or studs 53 extend into 7 plate; The depending ribs that heat taken up by occupy the'whole of the a, small margin being left for expansion. The space within the plate is between the flange 55 and the upper part of the plate, and to facilitate assembly the two parts are first secured together by screws BI and then their peripheral meeting edges are welded togetheratBZ. l f I 7 plate the fins, ribs or studs depending from it may be so designed that they provide draught-inducing passages'for the prod nets of combustion from the burner or burners, and if the plate has an annular depending peripheral wall openings are provided at suitable points for the escape of the tion. Channels on the underside ofthe cooke top may lead to a chimney or ventilator.

t A cooker top may conveniently consist of three a' plurality of vertically-elongated solid metal ic inserts formed of a material of The lower part has The filling. does not completely. space within the plate,

sealedby a washer v for positioning in the top of a stove higher heat conductivity than the plate disposed within the plate and the depending members.

2. A device according to claim 1, in which the upper ends of the inserts are flush with the upper surface of the plate.

3. A device according to claim 1, in which the inserts are disposed wholly within the plate and the depending members.

4. A device according to claim 1, in which the plate has a plurality of vertically-elongated apertures therein within which the inserts are positioned by a drive fit.

5. A device according to claim 1, in which the plate has a. plurality of vertically-elongated internally screw-threaded apertures therein within which the inserts are screw-threaded.

6. A device according to claim 1, in which the plate has a plurality of vertically-elongated apertures within which the inserts are positioned and which are respectively of greater diameter and length than the inserts therein, and a heat conducting material which is liquid at the normal operating temperature of the plate within the aperture.

' RICHARD HERMANN. 

